The invention relates to a hydrostatic multi-motor drive.
A hydrostatic multi-motor drive is known from FR 2 709 454 A. The hydrostatic multi-motor drive comprises a total of four adjustable hydraulic motors. To subject the hydraulic motors to pressure medium, a hydraulic pump connected to a driving engine is provided. Depending on the direction of travel, the likewise adjustable hydraulic pump delivers to a first and a second working line. In order to synchronise the hydraulic motors with one another in pairs, the hydraulic motors are connected to one another in series in pairs. A first hydraulic motor pair is connected to one another via a first working line section. Likewise, the second hydraulic motor pair is connected to one another via a second working line section. When there is a flow through in each case both hydraulic motors of a hydraulic motor pair, the two hydraulic motors of the hydraulic motor pair are synchronised with one another, since a constant volume flow flows through both hydraulic motors.
In order to improve the efficiency during normal driving, where, for example, only one hydraulic motor of each hydraulic motor pair is to be driven, there is a bypass line, by which the respectively downstream hydraulic motor of each hydraulic motor pair is bypassed. The pressure medium flowing through the respectively upstream hydraulic motor is thus led past the downstream hydraulic motor, with the result that the counterpressure for the upstream hydraulic motor falls. The efficiency of the upstream hydraulic motors thus increases. In order to be able to switch between a locked operating state and the optimised-efficiency state, a valve unit which can interrupt the bypass line is provided.
In the case of the multi-motor drive known from FR 2 709 454 A, it is a disadvantage that, owing to the simple short-circuiting of the two connections of the downstream hydraulic motor of each hydraulic motor pair, the inlet-side pressure of the downstream hydraulic motor falls practically to the suction pressure of the hydraulic pump. The respectively downstream hydraulic motor of each hydraulic motor pair therefore has to be coupled to the drive train of the vehicle, again resulting in losses. These losses have an adverse effect on the overall efficiency of the multi-motor drive.
It is therefore the object to provide a hydrostatic multi-motor drive having an improved efficiency.